Critical Values and Reference Ranges

Critical Value and Reference Ranges

A critical laboratory value is a value at such variance with respect to normal that it represents a pathophysiologic state which is life-threatening unless some action is taken in a relatively short time and for which an appropriate action is possible. The "links" below represent the critical values currently defined in the laboratory system.

The ranges and values listed are taken from the current literature, manufacturer's ranges, or have been determined within Legacy Laboratory Services. Ranges for young persons (under 20 years) or older patients (over 60 years) frequently are different than those listed for adults (ages 20-60 years). Some reference ranges also vary by gender or physiologic state of the patient. Legacy Laboratory Services routinely reports age-related reference values for many tests. If no age is provided on the requisition the reference range defaults to the adult reference range. For optimum reference range information to be returned on your reports, it is essential that Legacy Laboratory Services be provided with the patient's date of birth.

The following reference ranges are available on the website. Individual test reference ranges are available in the Test Table.